Zellio.io

Text Summarizer

Extract the key sentences from long passages — 100% on-device.

Processed locally — nothing is uploaded

About Text Summarizer

The summary is extractive: it selects sentences that already exist rather than writing new ones, so nothing is invented or paraphrased. The wording stays faithful to the source, but a rambling original still produces a rambling summary.

Paste a long article, report or document and extract its most important sentences into a concise summary. It ranks sentences by relevance using an on-device algorithm, giving you a quick TL;DR without reading every paragraph.

No AI service is involved, so there is no cost, no rate limit and nothing queued behind other people's requests. Adjust how many sentences to keep and copy the result in one click.

Learn how this works

Working With Text: Case, Diffs, Fonts & TranslationChange case, compare versions, generate fancy fonts, summarize and translate text — a guide to fast, private text tools.6 min read

Frequently asked questions

Is my document sent to an AI service?

No. Summarisation runs locally using an extractive ranking algorithm — no external AI API is called and nothing is uploaded. The tool scores each sentence by its relevance to the overall text using statistical analysis, then extracts the highest-ranking sentences to form a summary. This approach keeps sensitive company documents, confidential reports, and personal information completely private and on your device. Because no cloud API is involved, summarization works offline after the page loads and requires no authentication or account login.

How does the summary choose sentences?

It scores each sentence by how central it is to the overall text and keeps the highest-ranked ones, preserving the original wording. The scoring algorithm analyzes word frequency, sentence position, and relationship to the main topics to identify the most important sentences without rewriting. This extractive approach means you always get verbatim text from the original document, which preserves the author's voice and ensures accuracy for factual documents. You can adjust how much of the original document to keep (e.g., 25%, 50%, 75%) to get a shorter or longer summary.

Is it free?

Completely. There is no sign-up, no account, no watermark and no usage limit. The tool is supported by unobtrusive ads, not by selling or processing your data.

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